>>but the image in the ti-sdk does not, can you help me about this?
If you are referring to the TI Arago based SDK there is some udev info here that might help you:
http://e2e.ti.com/support/arm/sitara_arm/f/791/p/275113/960765.aspx#960765
http://e2e.ti.com/support/arm/sitara_arm/f/791/p/211868/750126.aspx#750126
http://e2e.ti.com/support/arm/sitara_arm/f/791/p/182986/676741.aspx#676741